Railway crossing gate



June 27, 1944. H. s. BROWN ET AL 2,352,310

RAILWAY CROSSING GATE Filed April 8, 1941 4 sheets-sheet 2 @ffii/.5.

June 27, 1944. H s, BROWN ET AL 2,352,310

RAILWAY CROSS ING GATE Filed April 8, 1941 v 4 Sheets-Sheet 5 June 27, 1944.

H. S. BROWN ET AL RAILWAY CROSSING'GATE Filed April 8, 1941 4 Sheets-Sheet 4 Patented June 27, 1944 UNITED STATES PATENT OFFICE RAILWAY CROSSING GATE Application April 8, 1941, Serial No. 387,480

Claims.

Our invention relates to railway crossing gates of the kind used at intersections of railways and highways to warn and protect pedestrians and highway vehicles from injury.

An object of our invention is to provide a railway crossing gate of the power-Operated type which is locked in all positions in normal operation, and which is automatically lowered by gravity in case of a power failure.

Another object of our invention is to provide a railway crossing gate having improved mechanism for permitting horizontal swinging of the gate arm if struck by a vehicle.

Another object of our invention is to provide a railway crossing gate having improved operating mechanism.

Another object of our invention is to provide a railway crossing gate which may be readily adjusted for different speeds of operation.

Another object of our invention is to provide a railway crossing gate having improved switchoperating mechanism.

Another object of our invention is to provide a relatively simple and inexpensive railway crossing gate which consumes a minimum of current.

Other objects and advantages will become apparent as the description proceeds.

In the drawings:

Fig. 1 is a vertical elevation of a crossing gate embodying our invention, this elevation being partially cut away on the line I I of Fig. 2 to show part of the operating mechanism;

Fig. 2 is a horizontal sectional view taken on the line 2 2 of Fig. l;

Fig. 3 is a vertical section through the upper part of the crossing gate mechanism, and is taken on the line 3 3 of Fig. 2;

Fig. 4 is a partial vertical section taken on the line 4 4 of Fig. l, and shows the power failure release mechanism on an enlarged scale;

Fig. 5 is a sectional View taken on the line 5 5 of Fig. 4; and, y

Fig. 6 is a simplified circuit diagram of the main operating circuit.

Referring particularly to Fig. 1, it will be seen that we have illustrated therein a railway crossing gate comprising in general a stationary frame Ill, a head I2 rotatably mounted thereon, a gate arm I4, and a gate arm shaft I6 rotatably supported in. the head I2.

The frame Ill comprises a base I 8 adapted to be bolted or otherwise secured to a concrete block or other suitable support. Sides are provided with removable plates 22 to facilitate inspection, adjustment, and repair. The upper end of the frame is closed by a cover 24 carrying ball bearings 26 and 28 rotatably supporting a sleeve 30, which carries the head I2. Vertical movement of the sleeve 30 is prevented by shoulder 32 and nut 34.

The head l2 comprises a lloor 36 bolted or otherwise suitably secured to the upper end of the sleeve 30, sides 38, top 40, and cover 4I. The sides 38 may be provided with one or more removable plates 42 for inspection, adjustment, or repair. A ring 44 extending into a recess 46 in the head I2 excludes dirt from the joint between the rotatable head I2 and the frame I0.

In order to maintain the gate arm I4 in a plane transverse to the highway and still permit this arm to swing under the impact of a vehicle, we provide yielding means, which we shall now describe.

As best shown in Figs. 1 and 3, the top 24 of the frame I0 provides a pair of V-shaped cam surfaces 48 and 50. A spring-pressed roller 52 (Fig. 3) is associated with each of these surfaces and serves normally to maintain the head I2 in such position that the rollers rest in the low points of these cam surfaces.

Each roller 52 is rotatably mounted in a foot 54 having an upwardly extending leg 56 slidably received in a sleeve 58. Each leg has a cross pin projecting into slots 62 in the sleeve 58 to prevent rotation of the foot 54 and leg 56 around a vertical axis.

The sleeves 58 are secured to the top 4I) and provide annular seats 64 for springs 6B which engage the upper surfaces of the feet 54 and press the rollers into engagement with the cam surfaces 48 and 50, respectively.

The gate arm I4 and gate arm shaft I6 are normally oscillated by an electric motor lil mounted on the base I8 and connected to the gate arm shaft by suitable driving mechanism, which we shall now describe.

The motor 10 drives a pulley I2 connected by a V-belt 14 with a second pulley 16. The pulley 'l2 is preferably made in two parts, the part 'I8 having a hub which is adjustably threaded to a sleeve-like extension of the other part B2. The effective diameter of the pulley I2 can be varied by rotating the part 18 with respect to the part 82 and the parts can be locked in adjusted position by a set screw 84. The motor 1I! is pivotally mounted on the base I8 so that the requisite tension is maintained on the belt 14 for all adjustments of the pulley 12.

The pulley 16 drives Worm shaft 86 through a friction clutch 88 which is normally maintained in driving relation by spring 90.' The worm shaft 85 has a worm 92 which drives a nut 94 mounted on ball bearings 96 and 98. The nut 94 has threads |00 which engage the threads |02 of a threaded shaft |04. The threaded shaft |04 has a keyway |06 which receives one end of a key |08 attached to a gear ||0 mounted on a ball bearing ||2.

The gear I| and threaded shaft |04 are normally held against rotation by a latch I I4 having a projection |I6 engaging the teeth of the gear I0. The latch ||4 is slidably mounted in a part II8 which is attached to the housing |20 enclosing the worm 92, nut 94, and associated mechanism. As long as the current for operating the crossing gate does not fail, the latch I|4 remains in the position shown in Fig. 5.

The latch I|4 is urged outwardly to disengaging position by a spring |22 confined between the stationary part |I8 and the flange |24 of a. nut |26 threadedly secured to the latch |I4. A lock nut |28 serves to maintain the nut |24 in adjusted position. Outward movement of the latch I I4 is limited by a ball |30 mounted in a hole |32 in frame |34 attached to the housing |20 by plate |36.

A ball bearing |38 is located between the ball and the side |40 of the U-shaped frame |34, the bearing |38 being mounted in the yoke shaped end |42 of a rod |44 slidably mounted in the frame |34.

In Fig. 5, the bearing |38 is illustrated as being held against an adjustable stop |46 by a solenoid |41 which is always connected with the source of electrical energy for operating the crossing gate. As long as an adequate source of electrical energy is available to operate the crossing gate, the bearing |38 is maintained in the position shown in Fig. 5, but upon failure of this source,`

springs |48 and |50 move rod |44 upwardly, as viewed in Fig. 5, thereby permitting ball |30 and latch |I4 to move toward the left, as viewed in this gure. Spring |48 is confined between the frame |34 and a sleeve |52 adjustably secured to`V`t 7 the threaded end of the rod |44, and retained in adjusted position by lock nut |54. The second spring |50 is confined between the frame |34 and a nut |56 adjustably secured to the sleeve |52,`

and maintained in adjusted position by lock nut |58. A single spring could be used in lieu of the two springs |48 and |50, but our experience has shown that two springs result in better operation because of the more desirable force characteristics resulting from a selection of properly complementary springs.

As viewed in Fig. 5, the upper end of rod |44 is recessed at |60 to receive a nger |62 and spring |64 for urging this finger into contact with a block mounted on a strap |56 attached to the main armature |68 of the solenoid |41.

The solenoid |41 is of the conventional type wherein the main portion |58 of the armature comprises a transverse bar so that the maximumI force is exerted by the solenoid when this bar is in contact with the ends of the magnetic core. Since it is important that the minimum of current be consumed by the solenoid |41, which is always energized, we have provided the lost tion connection between the nger |62 and rod |44 to permit the solenoid to remain in its most efilcient operating -position without unnecessary refinement in the positioning of the solenoid relative to the frame |34. It will be understood that the spring |64 is stronger than the combined springs |48 and |50.

The solenoid |41 need exert only the lightest possible force in addition to the force necessary to overcome the springs |48 and |50 to hold the bearing |38 in the position shown in Fig. 5. After a power failure and after correction of the difficulties so that solenoid |41 is again energized, only a slight force is required to move bearing |38 back into the position shown in Fig. 5, the principal force exerted by the solenoid being utilized to compress springs |48 and |50. A feature of the latch control mechanism resides in the fact that as soon as the current to the solenoid |41 is reestablished, the gate-operating mechanism is immediately and automatically restored to normal condition, and if the gate is down at the time of such restoration, the gate arm will be returned to elevated position in the usual manner.

As best shown in Fig. 4, a split collar |10 formed of two semi-ciroular sections held together by bolts |12 secures the threaded shaft |04 to a second vertical shaft |14 which constitutes in effect a continuation of the 'shaft |04. The collar |10 has a lower flange |16 received in an annular recess in the upper end of the shaft |04 and an upper fiange |18 received in a similar annular recess in the lower end of the shaft |14. The shaft |14 has a reduced lower end |80 received in a cylindrical recess in the upper end of the shaft |04, and a shoulder |82 resting on the ball bearing |84. The extreme lower end |86 of the shaft |14 extends into the upper race of the ball bearing |84 and a needle bearing |88 is confined between the end I and the wall formed by the upper end of the shaft |04.

Referring particularly to Fig. l, it will be seen that the shaft |14 is mounted for sliding move ment in a bushing |90 in sleeve 30. Stop collars |92 and |94 are adjustably secured to the shaft |14 by set screws |96 and |98, respectively, and carry flexible gaskets 200 and 202 which, under unusual conditions, may engage adjacent ends of the sleeve 30 to limit extreme movement of the shafts |04 and |14.

The upper end of the shaft |14 is provided with a bore 204 for receiving the depending pin 206 of a yoke 206. The yoke is secured to the upper end of the shaft |14 in rotatable relation thereto by a set screw 2I0 which engages an annular groove in the pin 206.

The upwardly extending arms 2|2 and 2I4 of the yoke 208 carry a pin 2|6 pivoted in a cross head ZIB sliding in the guideway formed by arm 220 and the U-shaped guide 222 bolted or otherwise secured to the under side of the arm 220. The arm 220 is rmly clamped by bolt 224 to the gate arm operating shaft I6 so that upward or downward movement of the arm 220 as a result of vertical movement of the shafts |04 and |14 will rotate the gate arm shaft I6 and the gate arm |4 carried thereby. From an inspection of Fig. 2, it will be seen that we have illustrated the gate arm as having side members 226 and 228 secured to ends of the gate arm shaft I6 for rotation therewith.

A pair of collars 230 and 232 are adjustably secured to the gate arm shaft I6 by bolts 234 and 236, respectively. The collars 230 and 232 provide laterally projecting lugs 238 and 240 for engaging the upper end of a lever 242 pivotally mounted at 244. A link 246 is pivoted to the lever 242 intermediate its ends and is pivotally connected by an adjustable pin 248 to arm 250 on Switch control shaft 252.

A plurality of switch control fingers 254 are clamped to the shaft 252, and each linger is adjustably connected to one or more switch control rods 25% or 253. The rods 256 control switches located in the lower series of switch boxes 260 and the rods 258 control switches located in the upper series f switch boxes 262. Any desired number of. switch boxes may be provided for switches controlling the motor 10, alarm bells or other audible signals, flashing, and non-flashing lights, interlocking control circuits, and all other circuits which it is desired to control by the position of the gate arm. Y

In Fig. 6, we have shown a simplified diagram of the circuit for controlling the normal operation of the crossing gate. In this figure, we have shown a track relay 300 having leads 302 and 304 adapted to be connected to a source of electromotive force in parallel relationship to a section or sections of track adjacent the crossing. The relay 300 is normally energized to hold the switches 330 and 308 in elevated position. In this position, the two sets of parallel contacts of the switch 303 are closed, while the contacts of the switch 308 are open. The motor 10 is not operating, however, since the line 3|0 connecting this motor with the switch 305 is broken by a second switch 3|2, which was opened by engagement of the lug 233 with switch control lever 242. The complementary switch 3|4 in the line 3|6 connecting the motor 10 with switch 308 is closed.

When a train approaches the crossing, the wheels of the train short-circuit the solenoid 300, allowing the armature and switches 306 and 308 to drop under their own weight. This opens the contacts of the switch 306 and closes the contacts of the switch 303, establishing a closed circuit from battery lead 3|8 through switch 308, switch 3M, and conductor 3|0 to motor 10, which is also connected by lead 320 to the other side of the battery connected to lead 3|8. This causes vthe motor 10 to operate in a direction to lower the gate arm. As soon as lug 238 moves away from switch lever 242, switch 3|2 closes under the action of its spring. When the gate arm has moved to lowered position, lug 240 engages switch lever 242 to open switch 3|4. Opening of switch 3| 4 breaks the circuit to the motor 10, and the gate arm remains in its lowered position.

After the train has left the track section controlling the crossing gate, the relay 300 is again energized and raises the movable contacts of switches 30% and 303 to the position shown in Fig. 6. Since switch 3|2 is now closed, the motor 10 is energized in reverse direction and operates to raise the gate arm. When the gate arm reaches its upper limit, lug 238 shifts switch lever 242 to open switch 3|2 and thereby break the circuit to the motor.

We have found that a direct current motor with a split eld gives satisfactory results, and we havediagrammatically illustrated such a motor in Fig. 6. Other types of reversing motors may be used, however, and our invention is not limited to a crossing gate using a direct current split field motor.

The leads 322 and 324 of the solenoid |41 shown in Fig. 5 are connected to the same battery or other source of electromotfive force to which the leads 3|B and 320 are connected so that failure of this source will release the solenoid |41 and permit the springs |48 and |50 to shift bearing |38 from between. ball |30 and frame |40. This permits spring |22 to move latch ||4 outward from engagement with the teeth of gear ||0.

This gear is then free to rotate with threaded shaft |04. This shaft is provided with a steep pitch multiple thread, such as the septuple thread shown in the drawings. The nut 94 is held against rotation by the worm 92, but the weight of the shafts |04 and |14 is sufficient to cause shaft |04 to rotate in nut 94, thereby permitting both shafts |04 and |14 to dropl under their own weight, and to lower gate arm |4. Where the gate arm is in other than a truly vertical position, the weight of this gate arm will also assist in this automatic lowering as a result of power failure.

The shaft |14 is free to rotate in the bushing 90, and the swivel connection between this shaft and the yoke |08 provides for such rotation. There is considerable frictional resistance to rotation of the shaft |14, however, and we have thus provided the free-running swivel connection between the shafts |14 and |04 to permit practically frictionless rotation in case of power failure.

When the gate is first installed, the pulley 'i2 is adjusted to give the desired speed of operation of the gate arm, and the collars 230 232 are adjusted to give the desired limits of travel to this arm. After these adjustments have been made and the electrical circuits have been connected, our crossing gate is ready for operation. When the motor 10 is energized by the approach of a train, in the manner previously described, the pulley 12 is rotated and drives the pulley 1li through the belt 14. Power from the pulley l5 is transmitted through friction clutch 88 to worm shaft 8S, thereby rotating worm 02 and nut Sli. Threaded shaft |04 is held against rotation bi* key |00, and. rotation of the nut 04 moves shafts |04, |14, and arm 220 on gate control shaft H5 downwardly, thus lowering the gate arm M. In case the gate arm should strike the top of an automobile or other object, the friction clutch will yield to prevent injury to the mechanism.

In normal operation, the mechanism will continue to operate until the gate arm i4 assumes a substantially horizontal position, when the motor control circuit will be opened by switch 324, thus stopping the motor.

If the gate arm Hl is struck 'by a moving automobile, the gate arm and head l2 will rotate in a horizontal plane. This yielding of the gate arm tends to prevent injury to the gate arm and also to the vehicle which strikes it.

As the gate arm swings laterally, the rollers 52 will move upwardly on their tracks 48 and 50, compressing springs 63, which resist such movement. As soon as the vehicle which struck the gate arm is moved away from Contact with the arm, the head l2 and gate arm are returned to normal position by the force exerted by the spring 06.

When the train has passed the crossing, the motor 10 is again energized to revolve in the opposite direction and to raise the gate arm. If children should hang on the gate arm or this arm should meet other unusual resistance, the clutch will yield to prevent injury to the mechanism. In ordinary operation, the gate arm returns to its uppermost position when lug 23B strikes switch control lever 242 and opens the motor circuit.

In normal operation, the nut 3d. worm 82, key |08, and latch cooperate to lock the gate arm against accidental movement in ail positions thereof. It is only when the power fails that the latch ||4 releases and permits the gate arm t fall under the action of gravity. f

The switches which are controlled 'by the position of the gate arm are preferably of a type which are spring held in normal position. This normal position may be either open o-r closed, depending upon the function of the switch and the particular circuit in which it is located. A switch is only moved from no-rmal position when the lug 238 or the lug 240 engages the switch lever 242, and the switch is immediately returned to normal position upon disengagement of such lug from the switch lever.

While we have described our crossing gate as being particularly adapted for use at the intersections ci railways and highways, it will be understood by those skilled in the art that our invention is not limited to such use, but may be placed at any point on a lfiighway, walk, railroad, bridge, or other right of way where it is desired to provide a movable barrier against traffic, In such location, our novel crossing gate may be controlled by any desired type of electrical circuit and manual or automatic switch mechanism.

While we have illustrated and described only a single embodiment of our invention, it is to be understood that this invention is not limited to the details shown and described, but may assume numerous other forms. Dur claims, therefore, are not to be construed as limited to the details shown, but are intended to cover various modiications thereof.

We claim:

1. A crossing gate of the class wherein a gate arm is arranged to swing in a vertical plane under the normal control oi swing mechanism and a solenoid is provided to permit lowering of the gate arm upon failure of a power source, a motor for elevating said gate arm, said motor being adapted for connection to a source of current through said switch mechanism, driving means connecting said motor and gate arm and normally effective to lock said gate arm in elevated position, a latch associated with said driving means and releasable to permit said gate arm to lower under the action of gravity, a, spring for biasing said latch toward open position, a ball normally preventing movement of said latch under the force of said spring, a U-shaped frame providing guide means for said ball and an opposing wall, a bearing movable into and out of position between said ball and wall, an adjustable stop normally holda ing said bearing in substantially exact axial alignment with said ball, a slidable rod carrying said bearing, spring means for urging said rod to move said bearing out of alignment with said ball,

said solenoid being connected to said currentl source for moving said rod and bearing in opposition to said spring means, said solenoid havin-g a movable armature movable into and out of a position of maximum eliciency, and a lost motion connection between said rod and solenoid, whereby said solenoid may maintain said bearing in axial alignment with. said bal-l with the armature of said solenoid in said position of maximum efliciency.

2. A crossing gate of the class wherein a gate arm is raised or lowered by power operated means controlled by switch mechanism responsive to dierent positions of the gate arm and a solenoid is provided to control lowering. of the gate arm upon failure of a power source, comprising a reversible motor adapted to be connected to a source of current, a nut driven by said motor, a threaded shaft driven by said nut, said shaft and nut having steep-pitched threads, a latch normally preventing rotation of said shaft and spring for Cil disengaging said latch to idle position, a movable part normally preventing movement of said latch under the iniluence of said spring, said solenoid being connected to said current source and controlling the position of said ball, a crossing gate arm moved to raised or lowered position by said shaft, driving means connecting said shaft and crossing gate arm, and whereby the force of gravity acting on said gate arm and driving connections tends to move said threaded shaft to a position corresponding to lthe lowered position of said gate arm.

3. A crossing gate of the class `wherein a gate arm adapted to swing in a vertical plane under the influence of power operated means controlled by switch mechanism responsive to different positions of the gate arm and a solenoid is provided to permit lowering of the gate arm upon the failure of a power source, comprising a motor for elevating said gate arm, said motor being adapted for connection to a source of current, driving means connecting said motor and gate arm and normally eiective to lock said gate arm in elevated position, a latch associated with said driving means and releasable to permit said gate arm to lower under the action of gravity, a spring for biasing said latch toward open position, a frame providing a wall, a bearing movable into and out of position between said latch and wall, a slidable rod carrying said bearing, spring means for biasing said rod to move said bearing out of alignment with said latch, said solenoid being connected to said current source for moving said rod and bearing in opposition to said spring means, said solenoid having `a movable armature movable into and out of a position of maximum eiliciency, and a resilient connection between said rod and solenoid whereby said solenoid may maintain said bearing in alignment with said latch with the armature of said solenoid in said position of maximum efficiency.

4. In a power operated crossing gate of the class wherein a gate arm is raised and lowered and has switch mechanism for controlling the raising and lowering of the gate arm and a solenoid responsive to failure of the power source to permit said gate arm to assume operative position, the combination of a reversible motor adapted for connection to said power source through said switch mechanism, a worm driven by said motor, a worm wheel driven by said worm, a nut driven by said worm wheel, a threaded shaft driven by said nut, said shaft and nut being provided with threads permitting either to drive the other, a latch for preventing rotation of said shaft, means connecting said shaft with said gate arm whereby the latter is driven by longitudinal movement of said shaft resulting from rotation of said nut, a latch normally preventing rotation of said shaft, and means connecting said latch with said solenoid whereby failure of power releases said latch and permits rotation of said shaft with resulting lowering of said gate arm.

5. In a power operated crossing gate of the class wherein a gate arm is raised and lowered and has switch mechanism for controlling the raising and lowering of the gate arm and a solenoid responsive to failure of the power source to permit said gate arm to assume operative position, the combination of a reversible motor adapted to be connected to said source of power through said switch mechanism, a nut driven by said motor, a threaded shaft driven by said nut, said shaft and nut having septuple threads, a latch normally preventing rotation of said shaft,

a spring for shifting said latch to idle position, a ball normally preventing movement of said latch under the iniuence of said spring, means responsive to said solenoid for controlling the position of said ball, and driving means connecting said shaft and gate arrm so that the force of ygravity acting on said gate arm and driving connections tends to move said threaded shaft to a position corresponding to the lowered position of said gate arm whereby said gate arm is automatically lowered upon failure of said power source.

HUGH S. BROWN. SAMUEL T. COMFORT. 

